For months now, on my wife’s High Sierra MBP every security update needs to be installed twice. I install it once and it downloads, installs, and restarts. Then upon launching the updates section I see that it claims the update is still there. So I select to install it again and it does the exact same thing: download, install, reboot. Then finally it claims no new updates. It’s a super annoying bug. And it’s been left this way without a fix now for months if not years. I don’t know how many updates I’ve had to install twice just because of this. Ugh. 